1. Technical Field
The present disclosure relates to a semiconductor light source driving apparatus which drives semiconductor light source elements such as light emitting diodes and laser diodes, and a projection type display apparatus using the semiconductor light source driving apparatus.
2. Description of the Related Art
Unexamined Japanese Patent Publication No. 2009-302295 discloses a semiconductor light source driving apparatus capable of continuously driving series-connected light emitting diodes which have no disconnection failure to emit light and capable of informing a user of disconnection failure, even after disconnection failure occurs in one or more of the series-connected light emitting diodes.
The semiconductor light source driving apparatus includes: a plurality of series-connected light emitting diodes; a power supply circuit which supplies electric power to the series-connected light emitting diodes; and a detector which detects disconnection when the disconnection occurs in any one of the light emitting diodes. Further, the semiconductor light source driving apparatus includes resistors connected in parallel to the light emitting diodes, switching elements connected to the resistors in series, and an informing unit which informs disconnection.
The semiconductor light source driving apparatus further includes a controller which controls the switching element so that when disconnection occurs in any one of light emitting diodes, a current flows through the resistor connected in parallel to the light emitting diode having the disconnection. This arrangement enables lighting operation of the light emitting diodes other than the light emitting diode in which disconnection occurs. Then, the controller provided in the semiconductor light source driving apparatus controls the informing unit to inform the user of the disconnection.
By such a configuration, even after disconnection failure occurs in one or more of the series-connected light emitting diodes, the light emitting diodes having no disconnection failure can continuously be driven to emit light and the disconnection failure can be informed a user.